Process of preparing alkali cellulose



Oct. 9,1923. I 1,469,824

P. C. SEEL PROCESS OF PREPARING ALKALI CELLULOSE Filed Jam. 27, 1923 y Lw r9 5 f 4 @aii zexfi as 4 /////4 //////////4.'. v 1 Z I 2 5 IN V ENTOR.

' PM 059%, BY

. ATTOR EY processes.

PAUL (J. snnn-or ROCHESTER, NEW YORK, ASSIGNOR 'IO EASTN KODAK com;

PANY, 0F nocnnsrnn, NEW YORK, A CORPORATION or new YORK.

PROCESS OF PREPARING ALKALI CELLULOSE.

Application filed January 27, 1923. Serial NO. 615,4= 14.

To all whom a may concern:

Be it known that I, PAUL C. SEEL, a citizen of the 'United States ofAmerica, residing at Rochester, in the county of Monroe 5 and State ofNew York, have invented certain newand useful Improvements in Processesof Preparing Alkali'Cellulose, of which the following is a full, clear,and exact specification.

Thi invention relates to processes of preparing alkali celluloses,particularly those types which are suitable for the preparationof-cellulose ethers. One object of the invention is to provide simpleand reliable Other objects will hereinafter appear. 7

c In the accompanying drawing, which forms a part hereof:

- .Fig. 1 is a diagrammatic sectional view of a ball mill in which thefirst step of the 95 at the end of the first step;

Fig. 3 is a diagrammatic sectional view of the mill illustrating anotherstep in the process, and

Fig. 4 is a diagrammatic sectional View of the mill showing the finalstep of the process.

In the preparation of cellulose ethers it has been found that thepossibility of obtaining products having the desired characteristicsdepends to an unexpected degree n on the manner and thoroughness with wich the ingredients of the alkali cellulose are mixed. For example, ifthe ethers derived from improperly mixed alkali cellulose be used in themaking of films, the

latter will exhibit a very undesirable haze. I have discovered a simpleand reliable method of efi'ecting the mixture of the ingredients in thealkali cellulose to such an '5 extent that this haze is practicallyeliminated from ethers derived from it.

A mass of cellulose fibers, alkali and water in the proportionsdesirable for subsequent etherification is not easy to handle by meansof ordinary grinding, because it clumps up intoa resistant mass. I havefound, however, that'if a roughor incomplete mixture Y of theingredients in the desired proportions be first'formed into a largenumber of small compacted dense masses or units and then these bepulverized, the action is simple to carry through completely.

The preferred form of my invention will be described by way ofillustration, but the invention is not limited thereto, except asindicated in the appended claims. Referring to Fig. 1 the materials 1 tobe mixed. in the form of alkali cellulose are charged into a cylindricalball mill 2, along. with the grinding elements or balls 3, access to theinterior being had through the normally closed door 4. The charge may,for example, be 100 parts of cotton or wood cellulose or cellulosetissue; together with 200 parts of solid caustic soda and 250 parts ofwater.

With the door 4 closed the ball mill is then rotated, as will be readilyunderstood which lines theball mill 2. and the cover 4.

There may be also a dense lining on some or all of the balls. This isindicated dia grammatically in Fig. 2, the compacted mass being shown at11.

As indicated in removed along with the balls and the interior lining orcompacted mass 11 is broken up into small compacted dense pieces orunits 5 by any suitable tool or instrument 6. Qt course, any materialwhich has been compacted on the surfaces of the balls 3 and door 4 maybe similarly scraped or broken up.

The small compacted dense masses or clumps'thus obtained are chargedwith the balls 3 again intothe mill 2. 'The door 4 is closed and themill rapidly rotated. The compacted masses are then rapidly andthoroughly pulverized and the ingredients thereby are brought to theintimate state of admixture which is so essential for the.

best production of cellulose ethers.

The; etherification is, of course, carried out in any of the known orpreferred ways. An alkali cellulose having the ingredients in theillustrative roportions mentioned above may be charge finto an autoclavewith 400 parts of ethyl chloride for each 100 parts of cellulose 1n themixture. The autoclave can then be heated for say twenty-four hours attemperatures between 90 and 170 C. i

Fig. 3, the cover 4 is.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. The process of preparing pulverulent intimately mixed alkalicellulose which comprises the steps of forming the ingredients,including the cellulose and alkali, into small compacted dense massesand then pulverizing said masses.

2. The process of preparing pulverulent intimately mixed alkalicellulose which comprises the steps of forming the ingredients,including the cellulose and alkali,- into a compacted dense mass,dividing said mass into a plurality of small dense masses, and thenpulverizing said small masses.

3. The process of preparing pulverulent Laeasea intimately mixed alkalicellulose suitable for etherification, which comprises the steps offirst agglomeratin' caustic alkali, cellulose, and water into ensecompacted small lil'lltS and then reducing said units to power.

4. The process of preparing pulverulent intimately mixed alkalicellulose, suitable for etherification, which comprisesthe steps day ofJanuary 1923.

. PAUL C. SEEL.

